The Summer Triangle in November, and a 120mm Takumar

 The Summer Triangle is a broad asterism consisting of three bright northern-hemisphere stars:  Vega (α Lyrae), Altair (α Aquilae), and Deneb (α Cygni).  They are, respectively, the 5th, 12th, and 19th brightest stars.  Vega and Altair straddle the Milky Way on opposite sides, while Deneb lies squarely in the middle.  In spite of its name, this asterism is still high in the sky just west of the meridian in the early evening in November.

A Sony A7iii camera, Sony FE 20mm f/1.8 G lens, and a Hoya Sparkle-6 filter were used to take the next two images:

 

The Milky Way and the Summer Triangle

In the northeast, the constellation Auriga and the Pleiades star cluster were rising through some murky clouds and strong airglow.

 At the middle top of this image is the constellation Cassiopeia and M31, the Andromeda Galaxy.  The sky brighness this evening was in the range 21.2 to 21.3 mpsas, depending on direction.

The Super-Multi-Coated Takumar 120mm f/2.8 lens is a short-telephoto screw-mount lens manufactured by Asahi Pentax from 1972 to 1976.  The following image of the constellation Lyra is a 1:2 crop from the larger frame from the Sony A7iii.  Wide open at f/2.8, the lens exhibits some minor astigmatism in the corners, and some minor purple fringing, which was cleaned up in post processing.  This cropped image mostly excludes the astigmatic corners.

The constellation Lyra with the Takumar 120mm @ f/2.8.  Vega is the bright star.

 

Election-night stars

 The sky was clear Tuesday evening, so while waiting for election returns to come in I captured some stars setting over Bristol Head and some rising over Snowshoe Mountain.  OM-5ii camera + Sigma 56mm f/1.4 lens.

 

The handle of the Big Dipper over Bristol Head. 60 s, f/1.4

The Whirlpool Galaxy, M101, shows up as a small fuzzy patch to the left and up from center.  Here is a closer crop, in which the spiral arms are just detectable:

M101

 A diffusion filter creates a more dramatic version of this scene.  The effect is a bit too strong at this focal length.

softon filter

 

Corona Borealis. softon filter

Pleiades over Snowshoe Mountain. Tiffen black pro-mist 1/8 filter, 30 sec.

Another old Russian lens: Helios 44M-7

 The Helios 44M-7 is a 58mm f/2 screw-mount lens from near the end of the Soviet era.  Based on the serial number, this copy was likely manufactured in 1992.  I tested this lens with a Sony A7iii camera.  Like the previous tests with the 50mm Super-Takumar f/1.4 and Industar f/3.5 lenses, the results here show that this lens is not well-suited for astrophotography (and there was no reason to expect otherwise). 

Here is the lens mounted on the A7iii:

 

The following star images were obtained on 31 Oct.  There was some fairly strong red airglow that night, but it has been balanced out in post-processing.  Accurate focus was confirmed with a Bahtinov mask.

f/2.0

f/2.8

f/4.0

 This lens is horrible (for stars) wide open, just like the Super-Takumar 50mm.  It starts to become acceptable at f/4 in the center of the frame, but astigmatism is still present around the edges.

Here is a crop from the last image, at f/4:

 This shows three stars in the handle of the Big Dipper over the ridge line of Bristol Head.  Just up and left of center is a fuzzy patch which is the galaxy M101, the "Pinwheel Galaxy".  Based on star separations in this image, the true focal length for this lens is calculated to be 59.0 mm.

FYI, it seems Blogger has reverted back to serving up the original files, with correct filenames, for images uploaded directly from a computer.  I hope this persists. 

The Milky Way on Halloween

Today we are experiencing another deluge from the sky, but last night was clear.  An OM-5ii camera and an Olympus 8mm f/1.8 fisheye lens were used to capture a couple views of the Milky Way from the front yard.  The measured brightness of the moonless sky was 21.2 mpsas.  In the camera, strong red airglow was easily visible. The red hue has been balanced out in post processing.

 

The same photo as above, but with a digital 3x3 median filter applied.

3x3 median filter.  Note M31 visible near the top right edge.

no filter applied

Star-testing a Super-Takumar 50mm f/1.4 lens

 The 8-element Pentax Super-Takumar 50mm f/1.4 lens was manufactured between 1964-1966.  According to internet lore (likely accurate), Pentax pulled out all the stops to manufacture this lens and sold it at a loss in order to claim "King of the Hill" status.  It is venerated in the Pentax community.  My copy has a low serial number and was therefore probably manufactured near the beginning of that time window.

I chose to do these tests with the lens mounted on a micro-four thirds E-M5iii camera.  This was a wise choice, because the results show that the edge performance on a full-frame (35 mm, e.g. Sony A7iii) camera would likely be bad. (It is.  See the end of this post) FWIW, the K&F Concepts adapter easily allows infinity focus, confirmed with a Bahtinov mask, which is greatly appreciated.

Here are two images of the lens mounted on the camera:

 The following images illustrate the performance over a series of f-stops: 1.4, 2, 2.8, 4.  Wide open, this lens is useless (actually, horrible) for astrophotography.  On a micro-four-thirds sensor, it becomes usable only at f/2.8.  These images show the stars in the handle of the Big Dipper setting over the Bristol Head ridge line.  Based on star separations, the actual focal length of this lens is 51.2 mm.

f/1.4 (ugh. yes, focused with a Bahtinov mask)

 

f/2.0, getting better, but still bad

 

f/2.8, acceptable

f/4.0, best, but slow

Some more pics, all taken at f/2.8:

Sagittarius

 

Corona Borealis over Bristol Head

 

In the image above, the position of the recurrent nova TCrB (T Coronae Borealis) is circled. This nova has an assumed eruption period of 80 years, which would make the year 2026 the next expected date. So far, nothing.

 

Fomalhaut (Alpha Piscis Austrini) over the southern flank of Snowshoe Mountain.

 

Lyra.  The Ring Nebula (M57) is circled near the left edge.

Conclusion: This is not a good lens for astrophotography.  Back in the day (film photography with manual-focus lenses) it was generally known that most lenses performed best when stopped down two or three stops from wide open.  The results here illustrate that quite well. This lens was great in its time, but modern lenses with special-dispersion glass and aspherical elements are are far superior when used wide open.

 Finally, an image taken the same evening after the moon rose above the ridgeline of Snowshoe mountain.  Not the Takumar.  A Panasonic Leica 9mm, live-comp 1-hr exposure.

Leica 9mm @ f/2. 1-hr.

The sky was covered with thin clouds Thursday night, but some stars were showing through, so I managed to acquire a couple test shots with the Takumar on a Sony A7iii.  This camera has larger pixels and a thinner sensor stack.  It still looks bad wide open, with severe astigmatism in the corners.

 

Thursday night. Sony A7iii + Takumar 50mm @ f/1.4

 

Hunter's Moon +1

 The full Hunter's Moon occurred here on Sunday night, but the sky was not clear until Monday afternoon, after a mix of rain and snow in the morning.  I used an Astro-Tech AT80EDT refractor to capture the 98.6%-full Moon rising over Snowshoe Mountain on Monday evening and setting behind Bristol Head Tuesday morning.

 

Moonlit landscape Monday evening

The 1-hr exposure above was obtained with an E-M1iii camera and a 7Artisans 7.5mm f/2.8 fisheye lens.

 

Hunter's Moon setting Tuesday morning

It rained, and rained, and rained

 Clear skies have been in short supply lately, with record rainfall and widespread flooding in southern Colorado and northern New Mexico.  There was a brief reprieve yesterday, but now it is raining again.

Friday (23 Oct)

 This weather brings to mind a poem that we came across in a visitor log somewhere in the notoriously-rainy South Island of New Zealand back in 1990.  The author was anonymous.

Rain

It rained, and rained, and rained,
the average fall was well maintained.

And when the tracks were merely bogs,
It started raining cats and dogs.

After a drought of half an hour,
we had a most refreshing shower.

And then, most curious thing of all,
a gentle rain began to fall.

Next day but one was fairly dry,
save for one deluge from the sky,

which soaked our party to the skin,
and then, at last, -- the rain set in.

Anon 

(lightly edited).

(tracks = hiking trails)

(we = the wife and I.  She gets credit for transcribing it)